On this day, papal minister Pellegrino Rossi was assassinated in Rome. The killing helped trigger a rapid breakdown of authority in the Papal States’ capital and pushed events toward open revolution. It also set the stage for Pope Pius IX’s flight and the later proclamation of a republic.
With unrest escalating, Pope Pius IX left Rome in disguise and traveled to Gaeta in the Kingdom of the Two Sicilies. His departure created a power vacuum in the city and weakened the papal government’s ability to control events. From exile, the pope sought help from Catholic powers to restore his rule.
Voters elected a Constituent Assembly to decide a new political order for the Papal States. The election marked a major shift toward representative politics, even as the pope opposed participation from exile. The assembly’s work soon moved beyond reform and toward ending papal temporal (political) power.
The Constituent Assembly declared a Roman Republic, replacing the papal government in Rome. The new regime aimed to modernize the state and connect Rome to wider Italian nationalist goals. This proclamation quickly drew hostile attention from foreign governments that wanted the pope restored.
The Assembly replaced its earlier executive with a three-man leadership (a triumvirate): Carlo Armellini, Giuseppe Mazzini, and Aurelio Saffi. This change concentrated political direction during a military emergency and gave Mazzini major influence over policy. The triumvirate tried to keep the revolution organized while preparing for foreign intervention.
French troops landed and moved against the Roman Republic, officially claiming a mission connected to restoring papal authority. The intervention reflected the wider European reaction against the 1848–1849 revolutions and showed the Republic’s vulnerability to outside powers. It also turned Rome into a key battlefield of the Risorgimento (Italian unification movement).
French forces under General Oudinot attempted to take Rome but were pushed back by defenders, including volunteers led by Giuseppe Garibaldi. The unexpected resistance boosted the Republic’s morale and reputation. However, it also convinced France to escalate from an assault to a sustained siege.
French troops renewed their push against Rome, fighting hard around the city’s defenses. Even where defenders held, the action helped transition the conflict into a tightening siege that cut supplies and increased pressure on the Republic. From this point, the military balance increasingly favored the better-equipped French army.
A truce was negotiated as French forces gained the upper hand and Rome’s defenses weakened. The talks reflected the Republic’s dilemma: continuing the fight risked more destruction, but surrender meant the end of the revolutionary government. The agreement helped shape the final days of the Republic and Garibaldi’s withdrawal.
French forces took control of Rome, and the Roman Republic was overthrown. The collapse restored the path for papal temporal rule, backed by foreign military power. Politically, the defeat also became part of the Risorgimento story by highlighting both the limits of revolution and the strength of Italian nationalist commitment.
As French forces besieged Rome, the Republic approved its constitution. The document was notable for its liberal principles for the time, including civic equality and religious freedom (ending Catholicism’s privileged legal status as a state religion). Adopting the constitution during the siege showed the Assembly’s intent to leave a political legacy even if the Republic fell.
After Rome’s fall, Garibaldi led thousands of volunteers out of the city rather than accept capture, seeking refuge and a route to continue the nationalist struggle. The retreat—ending with a temporary refuge in San Marino—kept revolutionary networks alive even after defeat. Over time, the 1849 defense of Rome became a remembered turning point that helped shape later unification politics and heroes.
Roman Republic of 1849 and its Suppression (1849)